Have a 1975 1.8 with L-jet. It used to fire right up, but it sat in the driveway for a month or two. Now it takes a couple seconds of cranking and sometimes feathering the throttle a bit to get it to start when cold. Starts fine when hot.

I took a look at the AAR. Is this what the "open" position looks like on the AAR or should there be a bigger hole? There was a decent bit of moisture in there, but I couldn't see any corrosion.

The 1.8 L-jet AAR is unique to the 914, not interchangeable with D-jet, and only (pretty sure) with the 912e/ 1976. The late John Williamson (Otto's) had a fix for these...check around on Pelican forum see of it's there.

It's definitely the right part... part number checks out on PET. As far as I can tell it's working correctly, but is it letting enough air through when cold? Should the "slot" in the valve be more open?

Vacuum lines were replaced in the last year so other than the aar I don't know what could be causing the issue.

It's open, but hard to say just how open it is in the picture. The better question would be is does it close all the way? Try applying 12 volts to the valve, and watch it close.